| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1333756 | Journal of Solid State Chemistry | 2008 | 8 Pages |
The phase composition of two series of mixed Nb5+–Sb5+ double perovskites formed between the pairs Ba2EuNbO6–Ba2PrSbO6 and Ba2NdSbO6–Ba2NdNbO6 have been studied using synchrotron X-ray powder diffraction methods. In both series extensive phase segregation is observed demonstrating limited solubility of Sb5+ in these Nb5+ perovskites, irrespective of the precise structures of the double perovskite. Evidence for a monoclinic I2/m phase in the series formed between tetragonal I4/m Ba2EuNbO6 and rhombohedral R3¯ Ba2EuNbO6 is presented. It is postulated that this phase segregation is a consequence of competing bonding requirements of the Nb5+ and Sb5+ cations associated with their electronic configurations.
Graphical abstractThe incompatibility of Sb and Nb in single-phase perovskites is explored for two families of oxides, namely Ba2EuNbO6–Ba2PrSbO6 and Ba2NdSbO6–Ba2NdNbO6. Limited solubility of Sb5+ in these Nb5+ perovskites is observed, irrespective of their precise structure. This is apparently a consequence of competing bonding requirements of the Nb5+ and Sb5+ cations.Figure optionsDownload full-size imageDownload as PowerPoint slide
